In 1947/48 Jews were ethnically cleansed from the West Bank and Jerusalem. Afterwards they were expelled from most Arab and Muslim countries.

Yes, many scholars think the settlements in the West Bank are against international law.

Settlements do something for security. Israel is a tiny country and the West Bank is the high ground overlooking the coastal plain. From some points in the West Bank attackers can shell the main population areas easily, as has happened in the past. So taking land alleviates that strategic weak point. An attack on a settlement is one less attack on Israel or gives advance notice of bigger attacks. It also gives the IDF legitimacy to operate in the area to protect civilians. That’s the reasoning behind them.

Now, I‘m against settlements and the land theft and oppression of Palestinians that results from it.